This invention relates in general to a fixture for performing and more specifically where the tensile tests are performed at extremely high temperatures (greater than 2500 degrees Fahrenheit).
Performing tensile tests on advanced materials at extremely high temperatures poses many problems. Among the most critical are specimen alignment and gripping.
Elevated temperature testing is performed at several locations. Among these are Southern Research Institute, IITRI and EMTL. All of these institutions have unique approaches to high temperature testing.
Current state-of-the-art elevated temperature tensile testing uses hot grips. At elevated temperatures, transferring the load from the hot grips to the load train is problematic. The extremely high temperatures require the use of material such as graphite or silicon carbide. These materials have coefficients of expansion which are much lower than the metals used in the load train. This creates the possibility of fixture damage, or misalignment due to the differential growth at test temperature.
It is an object of the invention to provide a novel fixture for performing tensile tests at extremely high temperatures that incorporates a self aligning feature while avoiding thermal stress problems inherent in using different materials at elevated temperatures.
It is also an object of the invention to provide a novel fixture for performing tensile tests at extremely high temperatures that allows gripping a specimen without introducing thermal gradients in the specimen.